Howard Goodall looks at the extraordinarily fertile musical period between 1650 and 1750, in which many of the musical innovations we take for granted today were invented. The orchestra; the overture, which led, ultimately, to the symphony; satisfying chord sequences, which gave music a forward momentum; modern tuning, which, for the first time, allowed composers to move from one key to any other they chose, and for different instruments to easily play together; the concerto, the oratorio, and, not least, the piano.